Design And Numerical Simulation Of Novel Self-collimation Optical Splitters In Silicon Photonic Crystals

The self-collimation effect of photonic crystals provides a brand-new way of controlling the light propagation due to the unique dispersion properties of photonic crystal. Meanwhile, the optical devices based on silicon photonic crystals have advantages for small-size, whole-silicon material, high bandwidth and low-loss. Thus the self-collimation photonic crystal devices will be widely used in the integrated optics and optical communications. In this dissertation, by utilizing the plane wave expansion method and the finite-difference time-domain method to simulation, we have proposed and designed the novel Polarization-dependent 1×n optical splitter based on Mach-zehnder interferometer and novel Polarization-independent 1×n optical splitter based on self-collimation of photonics crystal in silicon. The main works are as follows:1. The 1×n polarization-dependent optical splitters (PDOSs) based on self-collimation photonics crystal in silicon. By utilizing self-collimation effect and the principle of multi-beam interference, we analysis the theoretical transmission spectra and the condition of being multi-output optical splitters based on cascaded self-collimation ring resonator (CSCRR) in TE modes and TM modes. By utilizing the self-collimation effect, we have designed the structure of optical splitters. The transmission spectra at output ports of each optical splitter are investigated by FDTD method. The simulated results agree well with the theoretical calculation.2. The 1×n polarization-independent optical splitters (PIOSs) based on self-collimation photonics crystal in silicon. Utilizing polarization dependence of the transmission spectra of the self-collimation Mach-Zehnder interferometer (SMZI) and polarization transmission matching (PTM) method, the SMZI can work as the 1×2 PIOS by selecting appropriate path length difference in the structure; utilizing FDTD methods, we find a special ring resonator formed by four beam splitters with splitting ratio to realize the 1×4 PIOS based on self-collimation ring resonators.The innovation of this article:it is verified that using cascaded ring resonators making the 1×5?1×6?1×7 PDOSs in silicon photonic crystal realized; Utilizing polarization dependence of the transmission spectra of the self-collimation SMZI and PTM method to realize the 1×2 PIOS; using FDTD method and the relationship of reflectivity beam splitter changing with radius, we find a special SCRR with specific splitting ratio, and the 1×4 PIBS has the same splitting ratio for both transverse-electric (TE) modes and transverse-magnetic (TM) modes; The silicon material in photonic crystal will be widely used in future because of its mature technique.